Green’s Dictionary of Slang

bloodies, the n.

menstruation.

1888-94

‘Walter’ My Secret Life V 962: In virgins—just inside the tube, prick-receiver, or vagina, and behind the piss-vent, is a little red film or membrane covering the hole [...] through which the monthlies, or courses, or bloodies, as they are called, and other cunt juices of the woman escape.